JP3888017B2 - DC circuit breaker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a DC circuit breaker having a discharge disconnector for discharging a built-in capacitor for safety when inspecting a contact, and in particular, the width of a mounting surface of a discharge disconnector having three switching contacts is It relates to a reduced DC circuit breaker.
[0002]
[Prior art]
FIG. 4 is a circuit diagram showing a configuration of a conventional DC circuit breaker. The DC main circuit 18 including the DC power source 1, the load 2, and the disconnector 3 is provided with the interrupting unit 4 and disconnecting units 9 and 9 of the DC circuit breaker 31. A circuit in the ranges 12A and 13A in the alternate long and short dash line is the DC breaker 31. In the DC breaker 31, a series circuit of the discharge disconnector 5 and the discharge resistor 21 is connected in parallel to the interrupter 4 via another disconnecting parts 10 and 10, and the capacitor 7 and the switch 6 are further connected in series. The commutation circuit 19 is connected in parallel. The discharge disconnector 5 includes two switching contacts 20 and 32 that are linked by a connecting rod 24. The switching contacts 20 and 32 are connected in series via the discharge resistor 21, and the serial connection point between the switching contacts 20 and 32 is connected to the ground 40. As will be described later, the part in the range 12A is placed on a cart that can be taken in and out, and the part in the range 13A is housed in a fixed cradle. The disconnecting portions 9, 9 and 10, 10 are closed by pushing the cart to the cradle side and opened by pulling the cart to the near side. The switch 6 is formed of a thyristor, and is closed by injecting a signal from the outside into the base. Further, the discharge disconnector 5 is opened and closed manually. During the operation of the DC circuit breaker 31, the disconnecting portions 9, 9 and 10, 10 are closed, the discharging disconnector 5 and the switch 6 are open, and the capacitor 7 is connected to a charging device (not shown). Is always DC charged. On the other hand, the main circuit 18 is energized by closing the disconnector 3 and the breaker 4.
[0003]
Next, a mechanism for interrupting the current flowing through the main circuit 18 by operating the DC circuit breaker 31 of FIG. 4 will be described. In response to a shut-off command from outside, the shut-off unit 4 is opened and the switch 6 is closed. As a result, an arc is generated between the contacts of the interrupting portion 4 and the charge of the capacitor 7 is commutated. This current is vibrated by the capacitor 7 and an inductance (not shown) of the commutation circuit 19, and forms a zero point of the current between the contacts of the interrupting unit 4. At this zero point, the arc between the contacts of the interrupting portion 4 is extinguished and the main circuit 18 is interrupted.
[0004]
On the other hand, in order to check the contact point of the interrupting unit 4, it is dangerous to discharge the charge that is always charged in the capacitor 7, so it is necessary to discharge the charge in advance. The discharge disconnector 5 is for discharging the electric charge charged in the capacitor 7.
Next, a procedure for discharging the capacitor 7 will be described. When the disconnector 3 of the main circuit 18 is in the open state, the cart is pulled out to the front side to open the disconnecting portions 9, 9 and 10, 10. In this state, the switch 6 and the switching contacts 20 and 32 of the discharging disconnector 5 are simultaneously closed, and the electric charge charged in the capacitor 7 is discharged. Although the discharge resistor 21 is not necessarily required, the current flowing through the discharge disconnector 5 is limited by the interposition of the discharge resistor 21, so that contact damage of the switching contacts 20 and 32 can be suppressed. Thereby, the life of the discharge disconnector 5 can be kept long.
[0005]
FIG. 5 is a main part rear view showing the configuration of the DC circuit breaker 31 of FIG. 4. The switching contacts 20 and 32 of the discharge disconnector are mounted side by side on the mounting surface 13B on the back of the cradle of the DC circuit breaker. The fixed contacts 26 and 33 of the switching contacts 20 and 32 are fixed to the conductor 25, respectively, and the fixed contacts 10A of the two disconnecting portions 10 and 10 drawn out from the inside of the cradle through the insulating bushing 11 respectively. , 10B. The fixed contacts 26 and 33 are in contact with the movable contacts 27 and 34, respectively, the left movable contact 27 is fixed to the operating shaft 8 via the insulating lever 22, and the right movable contact 34 is connected via the insulating lever 38. Thus, the support shaft 17 is rotatably supported. The middle portions of the two insulating levers 22 and 38 are connected by the connecting rod 24 described above. FIG. 5 is a diagram when the discharge disconnector is in a closed state.
[0006]
6 is a side view of the main part showing the configuration of the DC circuit breaker 31 of FIG. 4, and is also a view as seen in the direction of arrow B in FIG. A cart (not shown) is arranged on the left side of the cradle 13, and the movable contact side and the blocking portion of the disconnecting portion 10 are loaded on the cart. The disconnecting portion 10 is opened by moving the carriage to the left side, and the fixed contact (not shown) of the disconnecting portion 10 contacts the movable contact 10A by moving the carriage to the right, and the disconnecting portion 10 is closed. It is like that. A discharge resistor 21 disposed on the other side of the operation shaft 8 is connected to a movable contact 27 via a flexible power supply line 28 and to a fixed contact of the other switching contact. . The fixed contact 10 </ b> A of the disconnecting part 10 is fixed to the mounting surface 13 </ b> B of the cradle 13 via an insulating bushing 11. The fixed contact 10 </ b> A is pulled out to the right side of the insulating bushing 11 and connected to the switching contact 20. That is, the conductor 25 is fixed to the right end of the fixed contact 10 </ b> A, and the fixed contact 26 of the switching contact 20 is fixed to the conductor 25. The fixed contact 26 is composed of two conductor plates, and comes into contact with the fixed contact 26 so as to sandwich a sword-shaped movable contact 27. The operation shaft 8 extends through the lower part of the cradle 13 to the front side (left side) of the vacuum circuit breaker, and a handle (not shown) is provided at the left end. By operating this handle to rotate, the operating shaft 8 rotates, and as a result, the insulating lever 22 rotates, so that the open / close contact 20 contacts and separates. Note that the switching contact 32 (FIG. 5) of another discharge disconnector has the same configuration as the switching contact 20 and is attached to the other side of the fixed contact 10A.
[0007]
7 is a cross-sectional view taken along the line XX in FIG. The fixed contact 26 is composed of two conductor plates, and sandwiches the conductor 25 and the movable contact 27. The holding force of the fixed contact 26 is formed via the spring 23. The movable contact 27 is configured to slide in a direction perpendicular to the paper surface of FIG.
FIG. 8 is a main part back view showing a state in which the discharging disconnector of FIG. 5 is opened. By rotating the operating shaft 8 clockwise, the insulating lever 22 rotates clockwise, and accordingly, the connecting rod 24 presses the insulating lever 38 to the right, and the insulating lever 38 uses the rotating shaft 17 as a fulcrum. Rotate around. Thereby, the movable contacts 27 and 34 simultaneously rotate clockwise, and come into contact with and away from the fixed contacts 26 and 33, respectively.
[0008]
Returning to FIG. 4, when the switch 6 is a mechanical switch that is turned on by electromagnetic force, it is necessary to directly ground the connection portion between the switch 6 and the capacitor 7 of the commutation circuit 19 so that there is no danger. . In that case, the circuit configuration is as shown in FIG.
FIG. 9 is a circuit diagram showing a configuration of a different conventional DC circuit breaker. The commutation circuit 42 includes a series circuit of the capacitor 7 and a mechanical switch 43, and the capacitor 41 is connected in parallel to the commutation circuit 42. The discharge disconnector 60 is provided with a third switching contact 37 in addition to the switching contacts 20 and 32 described above. The switching contact 37 is interlocked with a connecting rod 39 and one end thereof is connected to the switch 43. And the capacitor 7 are connected at the other end to the ground 40. The rest of FIG. 9 is the same as the configuration of FIG.
[0009]
FIG. 10 is a main part rear view showing the configuration of the DC circuit breaker 31 of FIG. Another switching contact 37 made up of a fixed contact 35 and a movable contact 36 is arranged alongside the switching contacts 20 and 32 on the right side of the mounting surface 13B. The fixed contact 35 is fixed to the conductor plate 25, and the conductor plate 25 is supported by an insulating plate 51 fixed by a metal fitting 50 from the mounting surface 13 </ b> B, and is configured to supply power to the inside of the cradle 13. The movable contact 36 is fixed to the insulating lever 52 and is freely rotatable about the rotation shaft 44 as a fulcrum. Further, the middle of the movable contact 36 is connected to a connecting rod 39. The movable contact 36 is grounded via a flexible power supply line (not shown). The fixed contact 35 is conductively connected to the connection point between the switch of the commutation circuit and the capacitor inside the cradle 13. To open and close the discharge disconnector, when the operating shaft 8 is rotated, the insulating lever 22 is rotated and the connecting rod 39 is driven left and right. The other insulating levers 38 and 52 rotate in conjunction with the driving of the connecting rod 39. By the rotation of the insulating levers 22, 38 and 52, the switching contacts 20, 32 and 37 are simultaneously opened and closed. In addition, FIG. 10 is a figure in case the disconnecting switch for discharge exists in an open state.
[0010]
[Problems to be solved by the invention]
However, the conventional apparatus as described above has a problem that when the mechanical switch is used in the commutation circuit and three switching contacts are arranged on the mounting surface of the cradle, the width of the mounting surface becomes large.
That is, when the discharge disconnector is in an open state as shown in FIG. 10, the movable contacts 27 and 34 and the conductor 25 are close to each other. The separation distance A needs to be an appropriate value. For this reason, the left and right width D of the mounting surface 13B of the cradle 13 is increased, and cannot be accommodated in the left and right width d of the mounting surface 13B in the case of two switching contacts as shown in FIG. For this reason, the entire cradle has become large, and the DC circuit breaker has become expensive.
An object of the present invention is to eliminate the need for increasing the width of the cradle even if the discharging disconnector has three switching contacts.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a blocking unit interposed in a DC main circuit and a series connection of a capacitor and a switch connected in parallel to the blocking unit and DC-charged are provided. And a disconnecting switch having three switching contacts that are mounted on the same mounting surface and interlocked with each other, and two switching contacts among the switching contacts are connected in series. Both ends of the series circuit are connected in parallel to the blocking section, the series connection point between the two switching contacts is grounded, one end of the remaining one switching contact is grounded, and the other end is the capacitor and the switch In the DC circuit breaker that is conductively connected to the serial connection point, the adjacent switching contacts among the switching contacts are mounted so that the separation distance from the mounting surface is different. It may be so made is. Thereby, even if the adjacent switching contacts are brought close to each other, a necessary insulation distance can be secured between the switching contacts.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on examples. FIG. 1 is a circuit diagram showing a configuration of a DC circuit breaker 31 according to an embodiment of the present invention. A lever 53 is fixed to the operation shaft 45, and a connecting rod 48 is connected to the lever 53. The right end of the connecting rod 48 is connected to the middle of the insulating lever 38, and the lower end of the insulating lever 38 is supported on the rotating shaft 49 so as to freely rotate. On the other hand, the operating shaft 45 is also fixed to the insulating lever 22 at the back of the lever 53, and the middle of the insulating lever 22 is connected to the connecting rod 47. The right end of the connecting rod 47 is connected to the middle of the insulating lever 52, and the lower end of the insulating lever 52 is rotatably supported on the rotating shaft 44. The central switching contact 32 is disposed in front of the switching contacts 20 and 37 on both sides, and the fixed contact 33 is fixed to the fixed contact 10B of the disconnecting portion 10 via the conductor 25. The rest of FIG. 1 is the same as the conventional configuration of FIG. 10, and the same parts are denoted by the same reference numerals and detailed description thereof is omitted.
[0013]
FIG. 2 is a view taken in the direction of arrow C in FIG. However, it is a figure of the state by which the disconnector for discharge was closed. The fixed contact 10B of the disconnecting portion 10 is drawn to the right side of the insulating bushing 11 longer than the fixed contact 10A, and the fixed contact 33 of the open / close contact 32 is fixed to the fixed contact 26 of the open / close contact 20 from the mounting surface 13B of the cradle 13. It is configured to protrude further to the right. A flexible power supply line 29 is drawn from the movable contact 34 of the switching contact 32 and connected to a grounding point.
[0014]
FIG. 3 is a plan view of the main part of FIG. However, the fixed contact side of each switching contact is excluded. As described above, the insulating lever 22 and the lever 53 fixed to the operation shaft 45 are interlocked with the connecting rod 47 and the connecting rod 48, respectively. The connecting rod 47 is connected to an insulating lever 52 that fixes the movable contact 36, and the connecting rod 48 is connected to an insulating lever 38 that fixes the movable contact 34. Therefore, if the operating shaft 45 is rotated, the insulating lever 22 is rotated, and the connecting rod 47 and the connecting rod 48 are interlocked, so that the insulating levers 52 and 38 are simultaneously rotated. As a result, the three open / close contacts open and close simultaneously.
[0015]
Returning to FIG. 1, since the central switching contact 32 is configured to protrude forward from the mounting surface 13B of the cradle 13, the movable contacts 27 and 34 do not approach the conductor 25 and can be switched to the mounting surface 13B. The contacts can be attached close to each other. Therefore, the width of the cradle 13 can be set to d and can be the same as the width dimension d in the case where the two switching contacts in FIG. 8 are attached. Therefore, even if the discharge disconnector has three switching contacts, it is not necessary to increase the width of the cradle, and it is possible to suppress an increase in cost.
[0016]
Note that. In the embodiment of FIG. 1, the central switching contact 32 protrudes forward from the switching contacts 20 and 37 on both sides, but the switching contacts 20 and 37 on both sides protrude from the central switching contact 32 toward the front. Also good. That is, it is only necessary that adjacent switching contacts among the three switching contacts are attached so that the separation distance from the attachment surface 13B is different.
[0017]
【The invention's effect】
As described above, according to the present invention, the adjacent disconnecting contacts among the switching contacts are attached so that the separation distances from the mounting surface are different, whereby the discharging disconnector is provided with three switching contacts. Even if it is, the width | variety of a DC circuit breaker does not become large, and it can suppress that it becomes expensive.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing the configuration of a DC circuit breaker according to an embodiment of the present invention. FIG. 2 is a view taken along arrow C in FIG. 1. FIG. 3 is a plan view of the main part of FIG. FIG. 5 is a main part rear view showing the structure of the DC circuit breaker of FIG. 4. FIG. 6 is a side view of the main part showing the structure of the DC circuit breaker of FIG. FIG. 8 is a cross-sectional view taken along the line XX. FIG. 8 is a main part rear view showing a state where the disconnecting switch for discharging is opened. FIG. 9 is a circuit diagram showing the configuration of a different conventional DC circuit breaker. Back view of the main part showing the configuration of the DC circuit breaker [Explanation of symbols]
1: DC power source, 2: load, 3: disconnector, 3, 9, 10: disconnector, 4: interrupter, 5, 60: discharge disconnector, 6, 43: switch, 7,41: capacitor, 11 : Insulation bushing, 13: cradle, 13B: mounting surface, 18: main circuit, 19, 42: commutation series circuit, 20, 32, 37: switching contact, 21: discharge resistance, 22, 38, 52: insulation lever, 24, 39, 47, 48: connecting rod, 25: conductor, 26, 33, 35: fixed contact, 27, 34, 36: movable contact, 28, 29: feeder, 31: DC circuit breaker, 50: Metal fitting, 51: Insulating plate, 53: Lever

Claims (1)

Installed side-by-side on the same mounting surface with a shut-off section interposed in the DC main circuit, a commutation circuit connected in parallel to the shut-off section and connected in series with a DC-charged capacitor and switch And is composed of a discharge disconnector having three switching contacts interlocked with each other, and among the switching contacts, two switching contacts are connected in series and both ends of the series circuit are connected in parallel to the blocking portion, A DC circuit breaker in which a series connection point between the two switching contacts is grounded, one end of the remaining one switching contact is grounded, and the other end is conductively connected to a series connection point of the capacitor and the switch. In the DC circuit breaker, the adjacent switching contacts among the switching contacts are attached so that the separation distance from the mounting surface is different.

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